This invention relates generally to a quick change insert for a finishing arm and more particularly to a quick change insert system for a microfinishing arm on a microfinishing machine.
xe2x80x9cMicrofinishingxe2x80x9d or xe2x80x9csuperfinishingxe2x80x9d, as it is known in the art, is a surface finishing process wherein a grinding means is brought to bear against a workpiece which has been previously rough ground. Microfinishing is a low velocity abrading process which generally follows rough grinding. Because microfinishing incorporates lower cutting speeds than grinding, heat and pressure variants may be minimized to provide improved size and geometry control. Those skilled in the art recognize that surface quality or roughness is measured in roughness average values (Ra) wherein Ra is the arithmetical average deviation of minute surface irregularities from hypothetical perfect surfaces. Microfinishing can provide surface quality of approximately 1 to 10 xcexcin. (0.025 to 0.25 xcexcm). Bearing surfaces of crankshafts, cam shafts, power transmission shafts in similar machine components that rotate on journal bearing surfaces generally require this surface finish for satisfactory operation.
Conventional mass production microfinishing machines have the ability to finish all the bearing surfaces on a workpiece in one operation. These machines contain a plurality of abrasive tape segments which are aligned with respect to the bearing surfaces. In operation, the workpieces are rotated as the microfinishing machine causes abrasive tape segments to contact and thus finish the bearing surfaces. These large multi-abrading machines are capable of successive steps in one operation including rough grinding, grinding and microfinishing.
As is common in large scale production, failures may occur at one or more of the grinding areas or abrasive tape positions. As a result, workpieces may be produced with one or more bearing surfaces (but less than all bearing surfaces) which are not finished to the required surface quality specifications. In such cases, the grinding machine operator must then remove and scrap the defective workpiece. Because microfinishing is the final stage in surface treatment operations, i.e. after rough grinding and grinding, the scrapping of microfinished parts results in a substantial loss of both material and labor to the machinist.
Microfinishing processes are used in automotive applications in the manufacture, repair and rebuilding of internal combustion (IC) engines. Such engines not only require finely finished bearing surfaces for engine efficiency, but also for increased durability and longevity. In the initial manufacturing stage, crankshaft and camshaft bearing surfaces are microfinished to particular roughness specifications by previously mentioned, conventional mass production microfinishing machines.
In the repair or rebuilding stages, engine components such as crankshafts and cam shafts from faulty engines or older engines, are removed and reground to remove ten to thirty-thousandths of an inch of stock from the existing bearing surfaces. The bearing surfaces of these components are then polished or microfinished by placing the respective workpieces on a lathe and manually bringing a microfinishing material in contact with the rotating bearing surfaces. This microfinishing material is often a section of abrasive material mounted on a support correspondingly shaped to the bearing surface. It is generally recognized in the industry that these manual finishing operations are inadequate for achieving finished surfaces of standard quality.
Automotive repair and rebuilding operations reclaim and refinish workpieces from hundreds of various internal combustion engines with different designs. Programmably controlling a finishing machine to accept each individual workpiece that requires microfinishing from different internal combustion engines is uneconomical and inefficient.
The quick change insert system of the present invention has been developed to meet the need for a quick change in finishing inserts to decrease maintenance and repair down of microfinishing machines. and well as add greater flexibility and speed in insert type changes.
Accordingly, it is an object of the present invention to provide a quick change insert system for a finishing arm which allows insert change without the use of tools.
Another object of the present invention is to provide a provide a quick change insert system for a finishing arm which allows insert change using a press fit connection system.
A further object of the present invention is to provide quick change insert system for a finishing arm using different hardness qualities of polymers and metals to allow for a press fit connection that is manually operated.
It is a still further object of the present invention to provide a provide a quick change insert system for a finishing arm which uses various correspondly mated key and keyway shapes to allow for the press fit connection
It is yet another object of the present invention to provide a provide a quick change insert system for a finishing arm which uses various correspondly mated key and keyway shapes to allow for the press fit connection without the use external fasteners.
A more specific object of the present invention is to provide a quick change insert system for a microfinishing machine comprising an insert body having a connection side and a finishing side, the connection side including a keyway defined by a central wall and a pair of oppositely disposed sidewalls, the finishing side including at least one finishing support surface; and a finishing arm having an extending key including a central shoulder and a pair of oppositely disposed side walls wherein the insert body keyway and finishing key are correspondingly matingly shaped in a press fit relationship whereby the insert body is retained on the finishing arm during finishing.
Another more specific object of the present invention is to provide A microfinishing machine comprising a support table having a means for rotating a workpiece about an axis and a slide rail adjacent the axis, a base including a bore for slidably receiving the slide rail and movable with respect to the workpiece, a body affixed to the base defining a track adapted to be positioned adjacent the workpiece and having a pair of pivot pins spaced from the track, a slide movable on the track, a first arm and a second arm pivotable on the pivot pins, the arms having a first end adapted to receive a quick change insert system for finishing the workpiece and a second end, link means connecting the slide to the second end of the arms for moving the arms about the pivot pins to extend the arms from a treatment enabling position adjacent the workpiece to a treatment position wherein the surface grinding means engages the workpiece, actuating means for movably engaging the slide and the arms, the actuating means operative to move the arms between the treatment enabling position and the treatment position, and a sleeve affixed to the body for receiving and guiding the actuating means, and a support means affixable to the base for pivotally supporting the body with respect to the workpiece whereby the quick change insert includes a an insert body having a connection side and a finishing side, the connection side including a keyway defined by a central wall and a pair of oppositely disposed sidewalls, the finishing side including at least one finishing support surface, and a finishing arm having an extending key including a central shoulder and a pair of oppositely disposed side walls wherein the insert body keyway and finishing key are correspondingly matingly shaped in a press fit relationship whereby the insert body is retained on the finishing arm during finishing.
The above objects and other objects, features and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention to be taken in connection with the accompanying drawings.